grr...starting problems..any ideas?

[mustangII460]

First thing that pops in my mind is timing. Try warming it up again, then crank while someone moves the distributor a little. See if that changes anything.

Also if your compression went up with your rebuild, your stock starter may not be up to par, especially after its warm. I use a late model starter in my old Bronco with a 1,000 cranking amp battery.